Changes based on review.

Author: aardvark179

src/main/java/org/truffleruby/Layouts.java

@@ -10,6 +10,9 @@
 package org.truffleruby;
 
 import com.oracle.truffle.api.object.HiddenKey;
+
+import org.truffleruby.cext.ValueWrapperLayout;
+import org.truffleruby.cext.ValueWrapperLayoutImpl;
 import org.truffleruby.core.HandleLayout;
 import org.truffleruby.core.HandleLayoutImpl;
 import org.truffleruby.core.array.ArrayLayout;
@@ -146,5 +149,6 @@ public abstract class Layouts {
     public static final TracePointLayout TRACE_POINT = TracePointLayoutImpl.INSTANCE;
     public static final DigestLayout DIGEST = DigestLayoutImpl.INSTANCE;
     public static final SystemCallErrorLayout SYSTEM_CALL_ERROR = SystemCallErrorLayoutImpl.INSTANCE;
+    public static final ValueWrapperLayout VALUE_WRAPPER = ValueWrapperLayoutImpl.INSTANCE;
 
 }

src/main/java/org/truffleruby/cext/UnwrapNode.java

@@ -1,5 +1,6 @@
 package org.truffleruby.cext;
 
+import org.truffleruby.Layouts;
 import org.truffleruby.language.RubyBaseNode;
 import org.truffleruby.language.control.RaiseException;
 
@@ -14,7 +15,7 @@ public abstract class UnwrapNode extends RubyBaseNode {
 
     @Specialization(guards = "isWrapper(value)")
     public Object unwrapValue(DynamicObject value) {
-        return ValueWrapperObjectType.VALUE_WRAPPER.getObject(value);
+        return Layouts.VALUE_WRAPPER.getObject(value);
     }
 
     @Fallback
@@ -25,4 +26,4 @@ public Object unwrapTypeCastObject(Object value) {
     public static boolean isWrapper(TruffleObject value) {
         return ValueWrapperObjectType.isInstance(value);
     }
-}
+}

src/main/java/org/truffleruby/cext/ValueWrapperLayout.java

@@ -12,6 +12,11 @@
 import com.oracle.truffle.api.object.DynamicObject;
 import com.oracle.truffle.api.object.dsl.Layout;
 
+/**
+ * This layout represents a VALUE in C which wraps the raw Ruby object. This allows foreign access
+ * methods to be set up which convert these value wrappers to native pointers without affecting the
+ * semantics of the wrapped objects.
+ */
 @Layout(objectTypeSuperclass = ValueWrapperObjectType.class)
 public interface ValueWrapperLayout {
 

src/main/java/org/truffleruby/cext/ValueWrapperObjectType.java

@@ -9,6 +9,7 @@
  */
 package org.truffleruby.cext;
 
+import org.truffleruby.Layouts;
 import org.truffleruby.collections.LongHashMap;
 import org.truffleruby.language.NotProvided;
 
@@ -19,8 +20,6 @@
 
 public class ValueWrapperObjectType extends ObjectType {
 
-    public static final ValueWrapperLayout VALUE_WRAPPER = ValueWrapperLayoutImpl.INSTANCE;
-
     private static DynamicObject UNDEF_WRAPPER = null;
 
     private static DynamicObject TRUE_WRAPPER = null;
@@ -29,24 +28,24 @@ public class ValueWrapperObjectType extends ObjectType {
     private static LongHashMap<DynamicObject> longMap = new LongHashMap<>(128);
 
     public static DynamicObject createValueWrapper(Object value) {
-        return VALUE_WRAPPER.createValueWrapper(value);
+        return Layouts.VALUE_WRAPPER.createValueWrapper(value);
     }
 
     public static synchronized DynamicObject createUndefWrapper(NotProvided value) {
-        return UNDEF_WRAPPER != null ? UNDEF_WRAPPER : (UNDEF_WRAPPER = VALUE_WRAPPER.createValueWrapper(value));
+        return UNDEF_WRAPPER != null ? UNDEF_WRAPPER : (UNDEF_WRAPPER = Layouts.VALUE_WRAPPER.createValueWrapper(value));
     }
 
     public static synchronized DynamicObject createBooleanWrapper(boolean value) {
         if (value) {
-            return TRUE_WRAPPER != null ? TRUE_WRAPPER : (TRUE_WRAPPER = VALUE_WRAPPER.createValueWrapper(true));
+            return TRUE_WRAPPER != null ? TRUE_WRAPPER : (TRUE_WRAPPER = Layouts.VALUE_WRAPPER.createValueWrapper(true));
         } else {
             return FALSE_WRAPPER != null ? FALSE_WRAPPER : (FALSE_WRAPPER = createFalseWrapper());
         }
     }
 
-    protected static DynamicObject createFalseWrapper() {
+    private static DynamicObject createFalseWrapper() {
         // Ensure that Qfalse will by falsy in C.
-        return VALUE_WRAPPER.createValueWrapper(false);
+        return Layouts.VALUE_WRAPPER.createValueWrapper(false);
     }
 
     /*
@@ -57,19 +56,19 @@ protected static DynamicObject createFalseWrapper() {
     public static synchronized DynamicObject createLongWrapper(long value) {
         DynamicObject wrapper = longMap.get(value);
         if (wrapper == null) {
-            wrapper = VALUE_WRAPPER.createValueWrapper(value);
+            wrapper = Layouts.VALUE_WRAPPER.createValueWrapper(value);
             longMap.put(value, wrapper);
         }
         return wrapper;
     }
 
     @TruffleBoundary
     public static synchronized DynamicObject createDoubleWrapper(double value) {
-        return VALUE_WRAPPER.createValueWrapper(value);
+        return Layouts.VALUE_WRAPPER.createValueWrapper(value);
     }
 
     public static boolean isInstance(TruffleObject receiver) {
-        return VALUE_WRAPPER.isValueWrapper(receiver);
+        return Layouts.VALUE_WRAPPER.isValueWrapper(receiver);
     }
 
 }

src/main/java/org/truffleruby/cext/WrapNode.java

@@ -84,4 +84,4 @@ public boolean isWrapped(TruffleObject value) {
         return ValueWrapperObjectType.isInstance(value);
     }
 
-}
+}